Forge World is giving you a chance to expand your Adeptus Titanicus forces with a new variant of the Warlord Titan. You can get it bundled with the arms, or pick up the arms separately if you already have a titan body you'd like to add these new weapons to.

From the website:

Warlord Battle Titans stride over the battlefields of the Imperium, their thunderous tread heralding the destruction of the enemies of Mankind. A mainstay of the Collegia Titanica, Warlord Battle Titans are among the largest and most powerful war machines ever devised by the Mechanicum.

This bundle allows you to build a Warlord Battle Titan for your games of Adeptus Titanicus and equip it with arm weapons from a choice of two volcano cannons, a Mori quake cannon and a macro gatling blaster. This lets you outfit your Titan to face any foe and gives you plenty of options to use in your games.